Perspective difference between a 35mm and 50mm

Discussion in 'Nikon' started by sun_p, May 19, 2009.

  1. Hello experts,
    I have learnt a lot thanks to the experts on this forum. I had posted a question about the nikon 35mm f1.8 and some other lens related questions and got some great information. However, I got some replies like 35mm is too short for portraiture 50 mm is the classic range etc. So I though I will post this as a seperate question for other beginners like me.
    I have the Nikon D40 and 18-55 kit lens and intersts lie primarily towards Portraiture. I also use strobes and natural light.
    1. Some experts mentioned that 35mm is too short. 50mm is better. I just wanted to understand what exactly would the perspective difference be. I have tried taking snaps with my 18-55 at 50mm and at 35 mm and the different i see is that at the same distance, 35mm covers more body while 50mm is a little closer and covers less of the body. Now, then how does this make much of a difference? Meaning- Sine both are prime and have fixed focal lengths its just a matter of the photographer moving back and forth to cover the same right? If I use a 35mm f1.8, Lets say I stand about 6 feet away. If I change to a 50mm, I will probably have to stand 10 feet. So if I am able to do that, isnt that enough? why do then people say that 50mm is the ideal or classic portrait. As a beginner am I missing something, like 35mm makes the nose/ear etc bigger something like that? -which I dont see with my kit lens
    2. I guess with 35mm I just need to stand closer while with a 50mm I need to stand further away to cover the same or is there something else also that I need to keep in mind with changing focal length prime lenses. Even for a full body shot, I stand closer with a 35mm compared to 50mm to cover the same area!
    I wonder if I am missing something important. Hence, I posted this as a seperate question!
  2. Don't confuse field of view with perspective. They're not the same thing.

    The ONLY thing that changes perspective is distance between you and your subject. Forget the lens for a moment.

    Imagine that you're looking at someone's nose from two inches away. It will look large, compared to their ears. Of course, your brain naturally compensates for this to a certain extent, and you don't really think about it much when you're in the flesh looking at someone. But if you took a photograph of their nose from a few inches away, you'd see and really note that the nose looks large, compared to the ears. If you use the same lens and back up a few feet, the nose and the ears are (compared to you) much closer together, and the perspective effect is dimished greatly.

    Here's why: when you eye is two inches from a nose, the ears might be six inches from your eye. That causes perspective "distortion" (it's not really distortion, per se) just like when you're looking at one automobile that's ten feet away, and another that's fifty feet away from you. If you took the picture of those two cars from 200 feet away, the difference in distance between the two cars would be much less meaningful, and they'd seem more in porportion to each other (just like you'd hope that noses and ears would be)... but if you shoot that closer car from five feet away, it will look huge compared to the one that's now ten times farther away. Faces and body parts work the same way.

    Focal length has NO impact on perspective. It only determines how easy it is to fill the frame with your subject at different distances. From 15 feet away, your 35 and 50 lenses will produce the same looking person. But the 50 will fill the frame better with their body.

    But if you try to fill a frame with a person's shoulders and head using a 30mm lens, you're well within the distance where perspective will start to make the closer parts of their body look larger compared to the rest of them. Hope this helps.
  3. [Sunil N] "Meaning- Sine both are prime and have fixed focal lengths its just a matter of the photographer moving back and forth to cover the same right?"
    Right, but perspective doesn't change because of focal length, but because of distance between the sensor plane and the subject(s). This is the great thing about zooms, you can change cropping without simultaneously changing perspective. When you "foot-zoom", you alter perspective and the appearance of the subject.
  4. Perspective is the difference in size relationships between near and far objects in the photo.
    It is not controlled by the lens, but by where you stand or camera position.
    If you were to overlay photos taken from the same camera position with 35 and 50 mm lenses, they would overlay perfectly except for the extra angle of view of the 35 mm lens.
    Now if you move forward to take in the the same background with a 35 as a fifty from further back, FOREGROUND objects will be larger compared to the background with the 35 mm lens.
    Prove to yourself with Photoshop where you can overlay images. Put the 50 on top and reduce the opacity of that layer and you will see it matches what is underneath.
    Also just hold your thumb up and move it close to your eye. As you bring it up, it seems to grow in size in relation to distant objects.
    In portrait work, there is a sweet spot where facial features are correctly rendered in relation to each other, nose and ears to eyes. Too close and the nose grows. Too far back and the face looks flat. Sweet spot is 5 to 7 feet. Use different focal lengths to adjust the angle of view.
    Check out the link and google perspective in photography.
  5. Thanks Matt, so in photography, is there an ideal distance in portraiture where perspective will start to make closer body parts look not so appealing? I guess this distance would be fixed beyond which any FL will be okay? Is that correct?
    e.g, If lets say the ideal distance is 15 feet then after fifteen feet if I use a 85 mm, 50 mm, 30mm , 200 mm, etc should be fine whether i move back 18feet, or 20 feet?
  6. Sunil: In broad terms, yes. But this stuff can be very subtle. There are people who take full-length (standing) portraits of models on the beach using 300mm lenses from way far back. At that point, the foreshortening of the scene takes on a somewhat stylistic sense. But that can over-flatten the appearance of things, too. As Tobey mentions above, too much distance causes the three-dimensionality of the face/body to become overly flattened for some tastes.

    Some editorial portraits or more stylized fashion work may actually call for the heightened perspective of working close. Perhaps we want to emphasize the watch on someone's hand? Shooting from up close with a short lens can be very powerful, that way. But most people don't want their noses to be powerfully enlarged. Nor does someone with striking angular features want their face to appear flattened like a cardboard cutout. So, each portrait photographer has a distance sweet spot they like for certain looks. The focal length to use simply follows from there, depending on how much of the person (or group of people, etc) you want in the frame.
  7. Sunil, I guess the posts above already answered your questions. For portraits (i.e. head or head/shoulder) I always liked the 105mm focal length - or rather, as DX has taught me, I liked the perspective (relation between foreground and background). Though many advocate the 50mm on DX for portrait - I don't like the perspective and stick to longer focal lengths. 50mm (on DX) is great for full body shots but not for anything less than that - but that's just my opinion. Though the FOV of the 50mm on DX is that of a 75mm on film, perspective hasn't changed and it isn't flattering to a head portrait.
    By the same token, I am currently thinking about getting a 35mm lens - the FOV on a DX will be close to that of 50mm on film but of course the perspective will be that of a 35mm lens. I never liked 50mm on film - but DX not forces me to figure out if it was the FOV or the perspective. I believe the latter as the 50mm was always too long or too short.
  8. Others have made great points. I'd like to add that while focal length will not change perspective directly, it often changes the perspective of photographs indirectly. This is because the photographer may move closer or farther from the subject to get the framing they want given the field of view provided by that particular lens, as Matt mentioned. The common example these days is the ubiquitious point-and-shoot photo taken too close to the subject because the photographer got up close to compensate for the default wide angle setting obtained when the camera is first turned on. An aware photographer understands this issue and will move forward or back and change focal length as appropriate so they can obtain the desired framing from the desired perspective.

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